Quick-return turning method for threads

The invention discloses a quick-return turning method for threads. The method comprises steps as follows: A, determination of the pitch and the thread number: determining the lathe screw rod pitch P1, the workpiece pitch P2 and the thread length L; B, calculation of the return position: calculating the least common multiple pitch P' of the P1 and the P2 as well as the workpiece thread number n, and calculating the lathe tool return position M, wherein M is equal to L or ([L/P']+1)*P'; C, turning feeding: retracting a tool when a lathe feeds to the n thread, continuously rotating a workpiece, and stopping the lathe when the tool is moved to a position M away from a workpiece thread starting turning point or directly stopping the lathe; D, quick return: releasing a lathe opening and closing nut, performing turning, moving a tool rest to the workpiece thread turning starting feeding point by the aid of a quick handle of the lathe; continuous feeding: connecting the lathe opening and closing nut, performing feeding, and starting the lathe to cyclically turn threads according to Steps C and D. With the adoption of the method, the return time of thread turning and abrasion to a lathe screw rod and the nut can be effectively reduced, so that the turning efficiency and the lathe reliability are improved.